Process of converting cast-iron into ingot-iron and ingot-steel



' oxides remain admixed with the metal.

' perature and fluidity ot' the bath.

' UNITED STATES PATENT O EicE.

JACOB REESE, OF PITTSBURG, PENNSYLVANIA.

PROCESS OF- CONVERTING CAST-IRON INTO lNGOT-IRON AND lNGOT-STEEL.

SPECIFICATION forming part of Letters Patent No. 269,465, dated December 19, 1882.

Application filed March 25, 1881.

To all whom it may concern:

Beit known that I, JACOB REESE, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a certain new and useful I mprove'ment in the Process of Converting Cast-Iron into Ingot-Iron and Ingot-Steel;

nite and exact amount of carbon and manganese may be incorporated in the resulting metal.

In the conversion of cast-iron into ingot iron or steel by the Bessemer process the metalloids are oxidized by the blast. A portion of these It is the common practice to remove the oxides by means of a manganesic addition. In the practiceol' the Bessemer proc'essitis now considered absolutely necessary to have a certain amount of manganese in the steel to neutralize the redshortness, and as an excess over the essential amount is injurious it is highly important to secure a definite and exact amount in the metal. The amount of oxides present in the resulting metal at the end of the blow cannot be accurately determined, as it will vary with the amount of metalloids and their relation to each other, and theconsequent change in the tem- For these reasons no accurate determination can be made of the amount of manganese required to deoxidize the metal, so that in order to secure a complete deoxidation it becomes necessary to introduce manganese in excess, apart of which will not be oxidized, but remain in the metal, so that it becomes impossible to secure the presence ofa definite amount of manganese in the metal at the end of the process.

The object of this invention is to overcome this difficulty and to secure a definite and exact amonnt.of manganese and carbon in the resulting metal. This I effect by first deoxid'izing the previously decarbnrized and partially-oxidized metal by the use of silicon in the form ofa silicious pigiron, and without the use (No specimens.)

of manganese at that stage of the process; and when the oxides have been thus removed I charge the deoxidized metal with manganese and carbon, in the form of spiegeleisen or ferroinanganesc. By this method all the manganese and carbon charged will be found in the resulting metal. I prefer touse a silicious pigiron as high in silicon and as low in carbon as possible, in order that as little carbon be present duringthe deoxidizing period as possible;

and the spiegeleisen employed should be as free from silicon as possible, no silicon being employed in the final step of the process other than what may be unavoidably present as an impurity in the spiegeleisen.

In applying this improvement to the Bessemer process the metal is blown in the usual manner. The converter is then turned down, and a quantity of a silicious pig-iron is run into the metal. The silicon in the silicious pig will reduce the oxides and remove them from the metal to the slag. \Vhen the metal has been deoxidized, sutlicient spiegeleisen or ferro-inanganese is added to incorporate the desired percentage of carbon and manganese to the resulting metal. The metal is then emptied out oft-he'converter and further treated in the usual manner. By this method the oxides are removed by the silicon, and pass off ganese. Hence but little, if any, ebullition will take place when the silicious pig-iron or the ferro-manganese is added to the metal, and, the metal being in a state of rest, the gases will escape, and the resulting ingots will be more solid and free from blow-holes than when ebullition resulting from the oxidation of manganese takes place, it always does in the present practice.

Another advantage of my process is that the oxidation of the manganese is prevented, and the manganese which heretofore has gone into the slag as a manganic oxide is saved. In the presentpracticeofdeoxidizingBessemer-metal by the use ofmanganese the slag contains about twenty-five (25) percent. of protoxide of man ganese. The product of Bessemer ingots during the year 1880 in the United States was one million two hundred and three thousand one hun- ICC sand two hundred and fifty-three tonsof manthat thirty-six thousand and ninety-five tons died and seventy-three net tons. In ordinary practice eight percent. ofspiegel, containing an average of fifteen per cent. of'manganese, is used. Thus an aggregate of ninety-six thouganesic metal was used in the Bessemer process in this country in 1880. The amount required in the steel will not average over threequarters of oneper cen t., (.75,) or sixty thousand one hundred'and fifty-eight tons, thus showing of manganesic metal was lost in 1880, all the manganese in which was oxidized and carried away in the slag. This waste of manganese I avoid by using in the placeot' manganesic metal in the first or deoxidizing stage of my process pig metal high in silicon, which may he obtained at about the same cost as the ordinary Bessemer metal from which the charge is made. Hem-e nearly the entire cost ofmane ganese heretofore used as a deoxidizing agent is saved.

My process of deoxidizing molten iron with silicon is also applicable to the open-hearth process; butin either case care should be taken to use only such quantity of silicon as may be required, care being also taken to correctly determine the amount of carbon in the additions of the silicious pig-iron -and the ferro-nlanganese, so that the proper percentage of carbon in iy be incorporated in the resulting metal.

To secure the advantage of this improvement, the metal must be deoxidized by thesilicon before the manganesic metal is added, because if the silicious pig-iron and the ferromanganese or a silicious pig-iron containing manganese is added the manganese will be largely oxidized, and the protoxide of manganese will pass into the sla It is important to determine by analysis the amount of silicon that is contained in the silicious pig-iron used' for deoxidizing, and, as before stated, it isdesirable that theiron should be as high in silicon and as low in carbon as possible; but I have obtained excellent results by the use of a silicious pig which contained thirteen per cent. of silicon and four per cent. of carbon, and good results by the use of a silicious pig-iron which contained two and sixtenths (2.6) of silicon and four per can t. of carbon.

When a specially high quality of ingot iron or steel is desired I prefer to tap 0d the silicious slag before introducing the manganese a a final addition.

I am aware that it has been proposed to use silicon and manganese, either together or in succession, for the purpose of deoxidizing the metal, and after the iron has been deoxidized to introduce silicon and manganese as a final 1 charge; but this process differs from mine in two important particulars, and does not secure the final result which it is the object of my invention to attain. These differences are that in the previous process referred to manganese is employed together with silicon as the deoxiding agent in the first step of the process, and that silicon is used with the manganese as the final step, and after the iron has been deoxidized, the result of which is that in the first step of that process, if the manganese -and silicon are introduced together, it is the manganese which cheaply operates to deoxidize the iron, while the silicon remains to a great extent in the iron without being removed as slag; and even if the manganese isintroduced after the silicon, instead of with it, it would in passing through the manganesic slag partially reduce itand return some ofits bases to theiron and in either case a considerable and indeterminate amount of both silicon and manganese remain in the iron unoxidized; and, further, in the final stage of that process all the silicon added would remain in theiron, and the amount of manganese in the final product would be an uncertain quantity, owing totheexcess ofmanganese necessarilyemployed in theinitialstage. The purpose of my invention is to deoxidize the metal before the introduction of manganese and carbon, so that previous to the add ing of the final charge the iron may not only be deoxidized, but as nearly as practicable free from carbon and manganese, so'that thereby a definite amount of carbon and manganese may be added to the bath and remain in the resulting metal, my object being to obtain a metal having a known amount of carbon and manganese, and also to effect a saving of a large amount of carbon heretofore wasted.

What I claim therefore as my invention, and desire to secure by Letters Patent, is-

In the manufacture of pig-iron into caststeel or ingot-iron, either by the Bessemer or open-hearth process, after the iron has been decarburized and is yet in a fluid condition, the process of deoxidizing the iron and combining with the same a definite amount of manganese, which consists in adding silicious iron, as described, and, after the bath of iron has been thus deoxidized, adding the desired amount of manganese or manganese and carhon, whereby a resulting metal is obtained JACOB REESE.

\Vitnesses:

FRANK M. Reuse, WALTER REESE. 

